Swing-JFileChooser的使用

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JFileChooser文件选择器是Swing中经常用到的一个控件。它的使用主要包含以下几个参数：

1.当前路径。也就是它第一次打开时所在的路径，许多软件喜欢设置为桌面。

2.文件过滤器。通过设置文件过滤器，只有特定类型的文件是可见的，比如文本，音频，等。

3.选择模式。包含三种情况：仅文件, 仅目录, 文件或目录。

4.是否允许多选。

JFileChooser的参数当然不止以上4种，它还有很多高级选项，比如你可以对文件的显示图标进行定制等，由于不经常用，这里不再介绍。

有2个地方要注意：

1.文件过滤器建议使用FileNameExtensionFilter，它是FileFilter的子类，以非常方便的方法实现了过滤器。用法见代码。

2.getSelectedFiles()方法，它只在isMultiSelectionEnable()方法返回true是有效。也就是说，如果你不允许多选，则只能使用getSelectedFile()方法，否则只能得到一个空的文件列表。

下面通过一个demo来展示它的基本用法。

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package org.javacore.swing.JfileChooser;import java.io.File;
import javax.swing.JFileChooser;
import javax.swing.JOptionPane;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.filechooser.FileSystemView;/**
*
* @author pzy
*/
public class JFileChooserFrame extends javax.swing.JFrame { /**
* Creates new form JFileChooserFrame
*/
public JFileChooserFrame() {
initComponents();
} /**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() { fileFilterisBG = new javax.swing.ButtonGroup();
isMultiSelectBG = new javax.swing.ButtonGroup();
jPanel1 = new javax.swing.JPanel();
text_rb = new javax.swing.JRadioButton();
video_rb = new javax.swing.JRadioButton();
audio_rb = new javax.swing.JRadioButton();
all_rb = new javax.swing.JRadioButton();
jPanel2 = new javax.swing.JPanel();
jComboBox1 = new javax.swing.JComboBox();
multiSelect_rb = new javax.swing.JRadioButton();
singleSelect_rb = new javax.swing.JRadioButton();
jPanel3 = new javax.swing.JPanel();
jButton1 = new javax.swing.JButton(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setLocationByPlatform(true); jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder("文件类型")); fileFilterisBG.add(text_rb);
text_rb.setText("文本"); fileFilterisBG.add(video_rb);
video_rb.setText("视频"); fileFilterisBG.add(audio_rb);
audio_rb.setText("音频"); fileFilterisBG.add(all_rb);
all_rb.setSelected(true);
all_rb.setText("所有"); javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(text_rb)
.addGap(29, 29, 29)
.addComponent(video_rb)
.addGap(35, 35, 35)
.addComponent(audio_rb)
.addGap(39, 39, 39)
.addComponent(all_rb)
.addGap(32, 32, 32))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(video_rb)
.addComponent(text_rb)
.addComponent(audio_rb)
.addComponent(all_rb))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
); jPanel2.setBorder(javax.swing.BorderFactory.createTitledBorder("选择模式")); jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "仅文件", "仅目录", "文件或目录" }));
jComboBox1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jComboBox1ActionPerformed(evt);
}
}); isMultiSelectBG.add(multiSelect_rb);
multiSelect_rb.setText("可多选"); isMultiSelectBG.add(singleSelect_rb);
singleSelect_rb.setSelected(true);
singleSelect_rb.setText("不可多选"); javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addContainerGap()
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 144, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(multiSelect_rb, javax.swing.GroupLayout.PREFERRED_SIZE, 82, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(singleSelect_rb, javax.swing.GroupLayout.PREFERRED_SIZE, 82, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(14, Short.MAX_VALUE))
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(multiSelect_rb)
.addComponent(singleSelect_rb))
.addContainerGap(16, Short.MAX_VALUE))
); jButton1.setText("开始");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
}); javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
jPanel3.setLayout(jPanel3Layout);
jPanel3Layout.setHorizontalGroup(
jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel3Layout.createSequentialGroup()
.addGap(117, 117, 117)
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 139, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
jPanel3Layout.setVerticalGroup(
jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel3Layout.createSequentialGroup()
.addGap(26, 26, 26)
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(19, Short.MAX_VALUE))
); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(layout.createSequentialGroup()
.addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGap(84, 84, 84)))
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(8, 8, 8)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
); pack();
}// </editor-fold> private void jComboBox1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
String itemString = jComboBox1.getSelectedItem().toString();
if ("仅文件".equals(itemString)) {
fileSelectionMode = JFileChooser.FILES_ONLY;
} else if ("仅目录".equals(itemString)) {
fileSelectionMode = JFileChooser.DIRECTORIES_ONLY;
} else if ("文件或目录".equals(itemString)) {
fileSelectionMode = JFileChooser.FILES_AND_DIRECTORIES;
}
} private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
fileChooser = new JFileChooser();
//初始化当前路径
FileSystemView fsv = FileSystemView.getFileSystemView();
File homeFile =fsv.getHomeDirectory(); //这便是读取桌面路径的方法了
fileChooser.setCurrentDirectory(homeFile); //初始化文件过滤器
if (text_rb.isSelected()) {
filter = new FileNameExtensionFilter("文本文件", "log", "txt");
fileChooser.setFileFilter(filter);
}
if (video_rb.isSelected()) {
filter = new FileNameExtensionFilter("视频文件", "mp4", "mkv");
fileChooser.setFileFilter(filter);
}
if (audio_rb.isSelected()) {
filter = new FileNameExtensionFilter("音频文件", "mp3", "wma");
fileChooser.setFileFilter(filter);
}
//初始化选择模式
fileChooser.setFileSelectionMode(fileSelectionMode);
//是否允许多选
if (multiSelect_rb.isSelected()) {
fileChooser.setMultiSelectionEnabled(true);
}
else if(singleSelect_rb.isSelected()) {
fileChooser.setMultiSelectionEnabled(false);
} //打开文件选择器
int i = fileChooser.showDialog(this, "选择");
if(i == JFileChooser.APPROVE_OPTION){
StringBuilder sb;
if(fileChooser.isMultiSelectionEnabled()){
sb = new StringBuilder("您选择了以下文件："); File [] files = fileChooser.getSelectedFiles();
for (File file : files) {
sb.append("\n");
sb.append(file.getName());
}
}
else{
File file = fileChooser.getSelectedFile();
sb = new StringBuilder("您选择的文件是：");
sb.append("\n");
sb.append(file.getName());
}
JOptionPane.showMessageDialog(this, sb);
}
} /**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(JFileChooserFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(JFileChooserFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(JFileChooserFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(JFileChooserFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold> /* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new JFileChooserFrame().setVisible(true);
}
});
} private JFileChooser fileChooser;
private FileNameExtensionFilter filter;
private int fileSelectionMode = JFileChooser.FILES_ONLY; // Variables declaration - do not modify
private javax.swing.JRadioButton all_rb;
private javax.swing.JRadioButton audio_rb;
private javax.swing.ButtonGroup fileFilterisBG;
private javax.swing.ButtonGroup isMultiSelectBG;
private javax.swing.JButton jButton1;
private javax.swing.JComboBox jComboBox1;
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JPanel jPanel3;
private javax.swing.JRadioButton multiSelect_rb;
private javax.swing.JRadioButton singleSelect_rb;
private javax.swing.JRadioButton text_rb;
private javax.swing.JRadioButton video_rb;
// End of variables declaration
}